Once you delete fb, twitter, mail, quora, etc. from your phone, why not just carry an e-ink Kindle or a paper notebook/calendar and some kind of music player?
Anecdotally: OmniFocus, dictionaries, pzizz, Skype, all-in-one banking app, a decent camera. My iPad or an iPod touch would have all of those, but then I'd have to carry two devices (I'd need a dumbphone for occasional calls). No data plan, no notifications at all (except for some slow-moving badges), and I still love my iPhone.
Smartphones still have some utilities I depend upon e.g. I'd be lost most of the time if I didn't have the maps application and I don't believe that forcing myself to not be reliant on it would be a productivity gain.
